I wonder if you could find a Will for Edward Lewis .... to see if a daughter Ruth is mentioned. That would help!
Looked for an Edward born sometime in the 1780s-1790s buried in Bistre (will start there first). There is one, who died in 1866... address the Blue Bell, and was a publican. Lots of my Welsh ancestors ended up being publicans after doing something else - so could be him.
He did leave a Will, but unfortunately, it doesn't list a wife or daughter as executor!! Argh!!!
https://probatesearch.service.gov.uk/Calendar?surname=lewis&yearOfDeath=1866&page=8#calendarStill a possibility... but may be a wild goose chase!
You could check for deaths/burials in St. Asaph for Edward of the right sort of age too. Perhaps you could find a corresponding Will.
So, chasing down siblings, or parents' Wills doesn't seem to yield a definitive answer

. I would suggest you see if you can find some Bistre Monumental Inscriptions to see if any Lewis tombstones there could tell you anything useful. You might even consider ordering a Will or two - if anything looks likely.
All I can think of for now...
RK